Stitcher mechanism



une 2,1942. N. A. ANDERSON ,2 STITCHER MECHANISM I Original Filed Jan. 29, 1940 V n rlllll-ll-ll-l llv n rrn 0F bum/K INVENTOR NEL5 A. ANDEEfiON myj b HA5 ATTORNEY l gun-ED f STAT becomes jammed in the mechanism.

Patented June 2 19.42

as PATENT OFFICE v s'rrrcnaaMEonANIsM Nels A. Anderson, swan, c5111.. assignorio Fibreboard lroducts Inc.,

SanFrancisco, CaliL,

a corporation of Delaware l Original application January 29, 1940, Serial No. v

316,17 Divided and this application February 21, 1941, Serial No. 379,992 l 40mins.

This is a divisionjof my copendingapplication,

Serial n 316,170 fileddanuary 29, 1940.

My invention relatesto mechanisms for stitching or stapling sheet material; and more particularly to a safety device for such mechanisms. The broad object of my invention is to provide a device for stopping .a stitcher after apredetermined number of stitches havebee made "to prevent iniuryto the stitcher head in event Another object is to providela safety device of the character described having achangeable pressed to clear the blank. Since trip offers some resistance to movement the blank is sub- :lected to a certain amount of edgewise compression; sufllcient to true up the edges and square the fold.

stapling head 4 and the associated the stitching mechanism may comprise parts of the well known Latham stitcher. Other parts of the Latham stitcher are also preferablyemployed, such as trigger 9, stitch spacing feed rolls i ll and discharge rolls II. In accordance with the usual operation of a stitcher of this kind, the

control member fordetermining the number of l stitches made before the stitcher is stopped. 1

l The invention possesses other objects and features of advantage, some 0f'WhiCh,With the foregoing, will be set forth in. the following description of myinvention.- It is to be understood that I do not limit myself to this disclosureof species of my invention, as I may adopt variant embodimentsthereof within the scope of the claims.

Referring to the drawing: Figure 1 is a side elevational mechanism with whichmy safety device is associated.

Figure 2 is a showing the safety device. This device is mounted on the back of the stitcher housing relative to the side shown in Figure 1. l p l 1 v Figure 3 is a detail sectional view, taken in a plane indicated by line 3-4 of Figure 2, showing the safety device and its operative connection withthe drive shaft of the stitcher.

. In terms of broad inclusion, my improvements comprise a. stitcher, and safety means timed with the stitcher for stopping the latter after a predetermined number of stitches have been made. The safety device preferably includes a changeable control member for determining the number 01 stitches made before the stitcher is stopped.

In greater detail, and referring to the drawing, my improvements are shown in conjunction view ofa stitcher advancing blank first depresses trigger 9 which conditions the mechanism for operation, and then pushes trip 8 which engages a clutch (not shown) to start'operation of the stapling head. Other mechanism of the stitcherv then comes into i play to rock an arm I 3 and lower the upper stitch spacing feed roll I I against the blank. These rolls are driven intermittently to advance the blank between stitches. Afterthe trailing edge of the blank rides off trigger 9 the stapling head fragmentary elevational view shown in Figure 1, so the path of the blank is reversed as indicated by arrow l9. When trigger 9 isdepressed by a blank it causes latch arm ll til move against the tension of spring 2| and bear against roller. 22 of lever l8. Subsequent movement of trip 8 by the blank then starts the stapling head, one stitch being made for each revolution ofits shaft l6. Upon rotation of shaft IS the cam l'I depresses lever l8 and notch 23 of latch arm it engages over the lever roller to hold it down. Depression of lever l8 keeps the stawith a machine for stitching a folded blank, such as disclosed in my above mentioned application. The machine includes a pair of suitably driven l and anvil 6 of the stitching mechanism. After leaving rolls 2 a pusher foot .8 actuated through suitable linkage I engages the trailing edges of theblank and pushes the latter against a trip This trip is an element commonly associated with stitcher mechanisms and moves forwardly 45. nism (not shown) into play to lower the stitch feed rolls 2 mounted on frame 3 and arranged to advance a folded blank between stapling head under the vpressure of the advancing blankto I start the stitcher. after which the trip is depling head in operation and brings other mechaspacing roll ll against the blank. When the trailing edge of the blank rides off trigger 9 the latter retracts latch arm H to release lever it, which stops the stapling head and causes dis a charge roll I! to be lowered against the blank.

These parts of the Latham stitcher and the operation thereof are well known to those skilled in the art. It is also known that if a blank becomes jammed in the machine so as to hold trigger 9 down, the stapling head continues to drive staples in the sameplace. causing damage to trip 8 of 12 against the stitched blank and is fixed a ratchet wheel 29 engaged by a pawl 30 carried by arm 24. A changeable control element or cam plate 3| is removably secured to a side of the ratchet by studs 32, and has a series of peripheral lobes 33 adapted to engage a catch 34 fixed on latch arm H at the arm pivot 35. By this arrangement latch arm [4 swings back to release arm l8 from notch 23 when a lobe rides under the catch, thereby stopping the stapling head. A suitable brake 36 frictionally engaging the other end of shaft 25 prevents ratchet 29 from overrunning.

In the operation of this device, arm 24 is oscillated by cam I1 and cam plate 3| is thereby turned through an arc defined by one ratchet tooth for each revolution of shaft l6. Thus, the distance between lobes 33 limits the number of stitches that can be made before the stapling head is stopped, should a blank become stuck in the mechanism; it being understood from the above explanation that the safety device operates to stop the stitching head independently of control finger 9. With the twelve lobed cam shown in Figure 3 the stapling head will be stopped after five staples have been driven. By replacing the changeable cam plate with one of the same diameter, but having a different number of lobes, the

stapling head may be stopped after a greater or less number of stitches, depending upon the spacing between the lobes.

I claim:

1. In a blank stitching machine, a stitcher, means engageable with the blank for starting and stopping the stitcher, and safety means operating in time with the stitcher and independently of said means for stopping the stitcher.

2. In a blank stitching machine, a stitcher having a shaft, means including a lever movable from extended to retracted position for stopping the stitcher, a timing cam on the stitcher shaft for extending the lever, a latch for holding the lever extended, a control cam engageable with the latch for releasing said lever, and means actuated by the timing cam for moving the control cam.

3. In a blank stitching machine, a stitcher having a shaft, means including a lever movable from extended to retracted position for stopping the stitcher, a timing cam on the stitcher shaft for extending the lever, a latch for holding the lever extended, a control cam engageable with the latch for releasing said lever, and means including a ratchet actuated by the timing cam for moving the control cam.

4. In a blank stitching machine, a stitcher having a shaft, means including a lever movable from extended to retracted position for stopping the stitcher, a timing cam on the stitcher shaft for extending the lever, a latch for holding the lever extended, a control cam having a plurality of spaced lobes engageable with the latch for releasing said lever, and means actuated by the timing cam for moving the control cam.

NELS A. ANDERSON. 

